Red luminescent materials for LED (light emitting device) applications are known in the art. U.S. Pat. No. 8,153,025, for instance, describes a red light emitting material of the formula M1−yA1+xSi4−xN7−x−2yOx+2y. RE whereby M is selected out of the group comprising Ba, Sr, Ca, Mg or mixtures thereof, A is selected out of the group comprising Al, Ga, B or mixtures thereof, RE is selected out of the group comprising rare earth metals, Y, La, Sc or mixtures thereof and x is ≧0 and ≦1 and y is ≧0 and ≦0.2. This material is believed to crystallize in a structure type that comprises two individual lattice sites for rare earth metal incorporation, which leads to an improved lighting behavior.